SDLC models (Software development life cycle Models) are characterized as different approaches and are utilized amid project development.
These methodologies are likewise called as “Software Development Models” (e.g., incremental model, V-model, RAD, iterative model, Agile model, Prototype display and so forth). Each model takes after a specific life cycle to guarantee accomplishment in the procedure of programming development.
SDLC phases
1. Requirement analysis
2. Defining the Functional specifications
3. Design
4. Development
5. Testing
6. Deployment and Maintenance
Different type of SDLC models are
The Waterfall model
The Waterfall Model, the first model of SDLC to be presented, is exceptionally easy to comprehend and utilize. In a project, using waterfall model each stage must be finished before the following step can start.
This kind of programming approach is primarily used when there are no unverifiable software requirements. Toward the ending of each level, a meeting is held to decide whether the venture is following the correct way and whether to proceed or dispose of the project. In this model, testing merely begins after all the improvements are finished.
Advantages and disadvantages of this model
- This model is straightforward to utilize.
- In this model, stages are dealt with and finished in turns. Which suits milestone focused development.
- High measures of vulnerability and risks involved.
- No working programming is delivered until later in the lifecycle, which causes delayed testing cycle.
- Not a decent model for complex software developments.
- Not appropriate for the software where requirements are more prone to evolving, considering the client feedback
Where this model is used mostly
- This model is utilized when the prerequisites are exceptionally notable, clear and settled.
- Innovation is comprehended.
- There are no equivocal requirements.
- The development process is short-lived.
V-shaped model
The V-shape model of SDLC might be viewed as an expansion of the waterfall model and is an advancement model. Rather than moving down straightly, the procedure steps are bowed upwards after the coding stage, to frame the V shape.
Major difference between V-Model and waterfall model is, in waterfall model testing starts after developing is completed in V-model testing activities are started at requirements phase itself.
Advantages and disadvantages of this model
- Straightforward to utilize as projects moves very organized pattern.
- Functions admirably, where requirements are effortlessly comprehended.
- Suits to medium scale projects.
- As Testing starts from requirement phase, V-Model spares a great deal of time.
- There is no intermediate status update to the customer as project updates are available at final stage only.
- Not well planned for risk management.
Where is this model used mostly?
- The V-molded model ought to be utilized for little to medium software developments where requirements are characterized and settled.
- The V-Shaped model ought to be picked when adequate specialized assets are accessible with required skilled mastery.
Prototype Model
The fundamental thought in Prototype model of SDLC development is creating a software development lifecycle in light of known prerequisites.
Prototyping is an appealing thought for entangled and enormous frameworks for which there is no manual procedure or existing structure to help to decide the necessities.
Evolutionary and throwaway are some examples of this type of model. The model usually does not finish frameworks. The objective is to furnish a structure with general usefulness and satisfying some prioritized requirements first.
Advantages and disadvantages of this model
- Clients are conclusively associated with this model.
- Since in this approach, a working model of the framework is given, the clients show signs of better understanding and comprehension of the context being produced, than when starting out.
- Mistakes can be recognized considerably before.
- Faster client input is accessible prompting better arrangements.
- Fragmented or insufficient issue examination.
- Befuddling or troublesome capacities can be recognized.
- The incomplete application may cause the form not to be utilized, especially in the throwaway model.
Where is this model used mostly?
- Prototyping guarantees that the end clients always work with the framework and give an input which is consolidated in the model to bring about a suitable structure.
They are incredible for planning great human PC interface frameworks.
Agile Model / Extreme programming
The agile model of SDLC is likewise a kind of Incremental model. Programming is produced in incremental, fast cycles. This outcome in little incremental releases with each release expanding on past inputs.
Each discharge is altogether tried to guarantee programming quality is kept up. It is utilized for time basic applications. XP, i.e., Extreme Programming is at present a standout amongst the most surely understood spry improvement life cycles.
Advantages and disadvantages of this model
- Consumer loyalty by fast, persistent conveyance of compelling programming.
- Clients, designers, and analyzers always communicate with each other.
- A working model is conveyed much of the time, i.e., weeks instead of months.
- Up close and personal discussion is the best type of correspondence.
- Close, day by day collaboration between developers and engineers.
- Persistent and excellent project outline.
- Customary adjustment to evolving conditions.
- Indeed, even late changes in requirements are invited.
- For huge projects, it is hard to evaluate the exertion required at the start of the product improvement lifecycle.
There is the absence of accentuation on necessary documentation.
Where is this model used mostly?
- When user input is more critical to the project, this model is being used.
- The task can, without much of a stretch, get taken off track if the client delegate isn’t explicit what ultimate result that they need.
Incremental Model
In the progressive/incremental model of SDLC , the entire prerequisite is separated into different forms. Numerous advancement cycles occur here, influencing the life cycle to a multi-cascade period.
In this model, every module goes through the necessities, outline, usage and testing stages. Each resulting arrival of the module adds up to the past release. The procedure proceeds until the entire framework is accomplished.
Advantages and disadvantages of this model
- Produces working product rapidly and ahead of schedule.
- This model is more adaptable – less exorbitant to change degree and necessities.
- In this model, the client can react to each module.
- This model needs excellent arranging and outline.
Needs an unmistakable and finish meaning of the entire frame before it can be separated and constructed incrementally.
Where is this model used mostly?
- This model can be utilized when the prerequisites of the entire framework are naturally characterized and comprehended.
- Real necessities must be characterized; be that as it may, a few subtle elements can develop with time.
There is a need to get an item to the market early.
Spiral Model
This model of SDLC is like the incremental model, with more accentuation put on risk examination. It has four stages: Planning, Risk Analysis, Engineering, and Evaluation.
A product venture over and again goes through these stages in cycles called Spirals. It is one of the product improvement models like Waterfall, Agile, etc.
Advantages and disadvantages of this model
- A high measure of hazard examination subsequently, shirking of risk is improved.
- Useful for huge projects.
- Solid endorsement and documentation.
- Extra functionality can be included later.
- Can be an exorbitant model to utilize.
- Risk investigation requires particular aptitude.
- It doesn’t function admirably for littler products.
Where is this model used mostly?
- Whenever expenses and hazard assessment is critical
- For medium to high-risk products.
- Clients are uncertain of their needs
- Prerequisites are perplexing.
Conclusion
All of the SDLC models are unique in their way, and we cannot restrict all projects to an ideal model. It all boils down to client preferences, the team and the type of project.